Prefilled cartridge syringe with needle system

ABSTRACT

A syringe system 1 for use with a prefilled injectate cartridge 9 comprises a hollow cylindrical barrel 2 having an outlet 3 at one end for passage of liquid to be expelled along a hollow pointed needle 5 by depression of a plunger 12. A protective sleeve 14 is mounted on the barrel 2 and is slidable along the barrel between a contracted position in which the needle 5 projects through an apertured end 15 of the sleeve 14, and an extended position in which the point of the needle 5 is located within the sleeve 14 to shield the point of the needle. Interengaging formations 22, 24, 26 on the barrel 2 and sleeve 14 are provided for retaning the sleeve 14 in the extended position, and a spring 19 is provided for resiliently biasing the sleeve 14 towards its extended position so that the sleeve 14 will automatically assume its extended position, and be retained therein by the interengaging formations 22, 24, 26, on release of pressure applied in the direction of contracting movement. Further interengaging formations 24, 23 are provided on the barrel 2 and sleeve 14 for retaining the sleeve in the contracted position to enable location of the needle 5 at the site of injection, the engagement of these formations being automatically released on depression of the plunger 12. Automatic shielding of the needle thereby takes place without requiring any specific operator action.

This invention relates to syringe systems.

After use of a syringe to perform an injection or take up a sample ofblood from a patient, there is a risk that doctors or nurses willaccidentally prick themselves with the needle of the syringe. Thisphenomenon is known as "needle stick" and can be highly dangerous due tothe risk of transfer of blood-related diseases.

European Patent Specification No. 0268445 discloses a fitment for asyringe in the form of a two-part protective sleeve which surrounds theneedle and which, together with the needle, is connectable to, anddisconnectable from, the needle connector of the syringe barrel in placeof a conventional needle. The sleeve has two sleeve parts which aremovable relative to one another from a contracted position, in which thepoint of the needle projects from the sleeve to an extent to enable aninjection to be effected, to an extended position, in which the point ofthe needle is located within the sleeve to shield the point of theneedle. During such movement the two sleeve parts are guided relative toone another by a projection engaging in a track, and a compressionspring within the sleeve ensures that the sleeve automatically assumesits extended position, and is locked in that position, after withdrawalof the needle from the patient.

Such a fitment is extremely effective in guarding against needle stickas it ensures that the point of the needle is shielded immediately afterwithdrawal from the patient without any need for operator action.Furthermore the fitment may be disposed of after use without any dangerof the point of the needle being re-exposed. Similar advantages areobtained in use of the syringe fitments disclosed in European PatentSpecification No. 0367398. However such fitments are in the form ofsealed units incorporating needles, and it is not possible forconventional needles to be fitted to such units or for the units to befitted to pre-filled syringes or pre-filled cartridge systems in whichthe needle is either supplied fitted to the barrel or in a common packfor fitting to the barrel. Also the sleeve is initially held in apartially contracted position in which only the tip of the needle isexposed when supplied for use, the sleeve being subsequently moved backby contact with the patient's skin as the needle is introduced into thepatient, and this can render the fitment unsuitable for certainapplications in which particularly accurate location of the needle at aninjection site is required or in which it is necessary for injectate tofirst be drawn into the syringe by inserting the needle into aninjectate bottle or vial.

It is an object of the invention to provide a novel form of syringesystem which guards against needle stick and which is capable of beingused in a number of applications for which the above-described fitmentis unsuitable.

According to the present invention there is provided a syringe system asdefined by the accompanying claims.

The protective sleeve of such a syringe system can be temporarily heldin the retracted position by the second retaining means in order toenable accurate location of the tip of needle at an injection site or toenable introduction of the needle into an injectate bottle or vial.Since the sleeve is retained in the contracted position away from thetip of the needle during location of the needle, rather than being heldin contact with the patient's skin as in the prior arrangement,sensitive control is obtained during location of the needle.Furthermore, after the point of the needle has been located in apatient's vein, the action of depressing the plunger to deliver therequired dose of injectate automatically results in release of thesecond retaining means so as to cause the sleeve to be moved to theextended position under the action of the biasing means and to beretained by the first retaining means in the extended position in whichit shields the point of the needle. Such a shielding action isautomatically initiated by the action of delivering the injection dose,so that safe shielding of the needle is not dependent on specificoperator action, and any risk of the needle being left accidentallyexposed after use is obviated. However the needle can be re-exposed ifrequired by taking specific manual action to release the first retainingmeans.

Such an automatic shielding action is advantageous in a number of fieldsof application, and finds particular application in a pre-filledcartridge system in which a pre-filled cartridge is introduced into thesyringe barrel and is punctured by a double-ended needle through whichinjectate is to be delivered to the patient under the action of aplunger. In such a system the needle is integral with the syringebarrel, and it is convenient for the needle assembly to be supplied withthe sleeve ready fitted to the barrel and locked in the extendedposition in which it surrounds the needle. This ensures that the needleis protected prior to use without having to be supplied with a removableprotective sheath. Furthermore the sleeve is retained in the extendedposition during fitting of the cartridge to the barrel and fitting ofthe plunger to the cartridge, and specific operator action is requiredto enable the sleeve to be moved back to the contracted position topermit an injection to be performed. Such action requires previousfitting of the cartridge to the barrel, so that the needle cannot beexposed either before the cartridge has been fitted to the assembly orif the cartridge is subsequently removed after an injection has beenperformed.

In order that the invention may be more fully understood, syringesystems in accordance with the invention will now be described, by wayof example, with reference to the accompanying drawings, in which:

FIG. 1 is an axial section through a first syringe system;

FIGS. 2 and 3 show the first syringe system partly in axial section andpartly disassembled, in two operational positions;

FIGS. 4 to 12 show schematic diagrams of the first syringe system indifferent operational positions, together with diagrams showing therelative positions of external ribs on the barrel and internal ribs onthe sleeve;

FIGS. 13 and 15 are side views of a second syringe system with theprotective sleeve in two operational positions;

FIG. 14 is an explanatory diagram showing location of a projectionwithin a track; and

FIG. 16 is a side view of the second syringe system during removal ofthe needle from the syringe.

Referring to FIG. 1, the syringe system 1 comprises a hollow cylindricalbarrel 2 made of transparent plastics material having at one end 3 anoutlet 4 through which a double-ended needle 5 extends. The needle 5 hasa first pointed end 6 for puncturing the patient's skin and a secondpointed end 7 for puncturing a rubber membrane of an end closure 8 atone end of a glass cartridge 9 which is pre-filled with injectate. Anactuator 10 comprises a collar part 11 which is a push fit over theopposite end of the cartridge 9, and a plunger 12 which is slidablewithin the collar 11 so as to displace a piston 13 within the glasscartridge 9 in order to expel injectate from the cartridge 9 along theneedle 5 in known manner.

In addition a transparent plastics protective sleeve 14 is mounted onthe barrel 2 and is slidable along the barrel 2 between a contractedposition (see FIG. 2) in which the needle 5 projects from an aperturedend 15 of the sleeve 14, and an extended position (see FIG. 3) in whichthe needle 5 is located within the sleeve 14 to shield the pointed end 6of the needle.

The sleeve 14 is provided with an outwardly projecting flange 16 at itsopposite end which is intended to be grasped during administration of aninjection to the patient. Furthermore the flanged end of the sleeve 14has an opening 17 into which an annular insert part 18 is force fittedduring assembly in order to retain the barrel 2 within the sleeve 14. Acompression spring 19 is located between an inner flange 20 on thesleeve 14 and a shoulder 21 on the barrel 2 in order to tend to bias thesleeve 14 towards the extended position.

As may be appreciated more readily by referring to the partiallysectioned views of FIGS. 2 and 3, the outer surface of the barrel 2 isprovided with a series of longitudinally extending external ribs 22.Although only two ribs 22 are visible in the figures, six such ribs 22are in fact equiangularly spaced about the circumference of the barrel2. Furthermore each rib 22 is provided at one end with a latch part 23.Furthermore the inner surface of the sleeve 14 is provided with firstinternal ribs 24 and second internal ribs 25 angularly offset from thefirst ribs 24.

The external ribs 22 on the barrel 2 cooperate with the internal ribs 24and 25 on the sleeve 14 and with six retaining recesses 26 in the insertpart 18 to guide the sleeve 14 on the barrel 2 and to provide therequired operational action which will be described below with referenceto FIGS. 4 to 12. Each of FIGS. 4 to 12 shows schematically, on the lefthand side of the figure, the syringe system 1 in a particularoperational state, and, on the right hand side of the figure, thepositioning of the external ribs 22 on the barrel 2 in relation to theinternal ribs 24 and 25 on the sleeve 14 and the recesses 26 in theinsert part 18. It will be appreciated that, for convenience, the ribs22, 24 and 25 and the recesses 26 in the insert part 18 are shown indeveloped view, and only some of these ribs and recesses are shown.

The needle assembly, that is the assembly of the barrel 2, needle 5 andsleeve 14, is initially supplied without a pre-filled cartridge 9 inposition, and with the needle 5 shielded within the sleeve 14 as shownin FIG. 4. In this position (corresponding to the position shown in FIG.3) the sleeve 14 is extended in relation to the barrel 2 so that theexternal ribs 22 on the barrel 2 engage within the recesses 26 in theinsert part 18 and the latch parts 23 of the external ribs 22 arepositioned so as to cooperate with the internal ribs 24 on the sleeve 14to prevent the needle 5 being exposed by accidental retraction of thesleeve 14. Furthermore, since the barrel 2 is wholly contained withinthe sleeve 14, there is no operation which may be performed on theassembly which will result in exposure of the needle 5 by retraction ofthe sleeve 14. With the needle assembly in this position a cartridge 9may be introduced into the sleeve 14 so as to cause the rubber membraneof the end closure 8 of the cartridge 9 to be pierced by the pointed end7 of the needle 5. The actuator 10 may then be engaged with the oppositeend of the cartridge 9 by movement in the direction of the arrow 40. Thecartridge 9 fits tightly into both the barrel 2 and the collar part 11of the actuator 10 in order to prevent relative rotation between thesecomponents in use.

A manual setting operation is then required in order to expose theneedle 5 so as to render the syringe system ready for use in carryingout an injection. In order to perform this setting operation, thesyringe system must be held in two locations, as shown by the arrows 41and 42 in FIG. 5, using two hands, and a twisting and pushing actionapplied to the sleeve 14, as shown by the arrows 43 and 44 in FIG. 5.This action causes axial displacement and rotation of the insert part 18relative to the barrel 2 so as to disengage the external ribs 22 on thebarrel 2 from the recesses 26 and cause the ribs 22 to engage rampsurfaces 27 on the insert part 18, as shown on the right hand side ofFIG. 5. Simultaneously the internal ribs 24 on the sleeve 14 are alignedwith the gaps between the ribs 22 so as to permit retraction of thesleeve 14 relative to the barrel 2 in a subsequent operation. It isimportant to appreciate that this unlocking operation cannot be achievedeither by means of a twisting action alone or by means of a pushingaction alone applied to the sleeve 14.

The sleeve 14 may then be retracted against the action of thecompression spring 19 by pushing in the direction of the arrow 45 toexpose the needle 5, as shown in FIG. 6. This causes the internal ribs24 on the sleeve 14 to pass through the gaps between the external ribs22 on the barrel 2, as shown on the right hand side of FIG. 6.

The sleeve 14 may then be temporarily locked in the retracted position,in which the needle 5 is exposed, by applying a twisting action to thesleeve 14, as shown by the arrow 46 in FIG. 7. The twisting actioncauses the internal ribs 24 on the sleeve 14 to be circumferentiallydisplaced relative to the external ribs 22 on the barrel 2 so that theribs 24 engage behind shoulders 28 on the latch parts 23 of the ribs 22to prevent the ribs 24 moving back through the gaps between the ribs 22under the action of the compression spring 19. This places the syringesystem in the contracted position in which it is ready for use forcarrying out an injection.

The sequence of steps for carrying out the injection are as follows. Thesyringe system is grasped in one hand in conventional manner with thesleeve 14 being held between the fingers in the vicinity of the flange16 and the thumb being applied to the end of the plunger 12 of theactuator 10. The needle 5 is first caused to puncture the patient's skinuntil the pointed end 6 of the needle 5 is at desired location at whichthe injection is to be made. A squeezing action is then applied to thesyringe system as shown by the arrows 47 and 48 in FIG. 8. Initiallythis action causes the sleeve 14 to be moved back slightly relative tothe barrel 2 so that the internal ribs 25 on the sleeve 14 engage rampsurfaces 29 on the latch parts 23 of the ribs 22 the barrel 2, as shownin FIG. 8.

Further squeezing of the syringe system causes the ribs 25 to ride alongthe ramp surfaces 29 and thus results in slight relative rotationbetween the barrel 2 and sleeve 14 to align the ribs 24 with the gapsbetween the ribs 22, as shown in FIG. 9. The resulting lockingengagement between the latch parts 23 and the ribs 25 prevents furtherretraction of the sleeve 14 relative to the barrel 2 and results indepression of the plunger 12 so as to move the piston 13 within thecartridge 9 and deliver the required dose of injectate along the needle5.

After delivery of the injectate the user's grip on the syringe system isrelaxed so as to enable the sleeve 14 to move towards its extendedposition in the direction of the arrow 49 under the action of thecompression spring 19, as shown in FIG. 10. During such movement theribs 24 pass back through the gaps between the ribs 22. Assuming thatthe needle 5 has meanwhile been removed from the site of injection, thesleeve 14 moves into its extended position shielding the needle 5, asshown in FIG. 11, resulting in engagement of the ribs 22 with the rampsurfaces 27 on the insert part 18.

The engagement of the ribs 22 with the ramp surfaces 27 causes a slighttwist to be automatically applied to the sleeve 14 as shown by the arrow50 in FIG. 12, and this results in the ribs 22 engaging within therecesses 26 in the insert part 18 resulting in the ribs 22 assuming thesame alignment relative to the ribs 24 as in the initial position shownin FIG. 4. The sleeve 14 is locked in this position by virtue of thefact that the latch parts 23 cooperate with the ribs 24 to prevent thesleeve 14 being retracted relative to the barrel 2. Thus the usedsyringe system (either with or without the actuator 10) can be safelydisposed of without risk of accidental re-exposure of the tip of theneedle.

It is to be noted that the needle 5 may be re-exposed if required,although such re-exposure can only be effected by means of the twistingand pushing action applied to the sleeve 14 as described above withreference to FIG. 5 so that there is no danger of such re-exposure beingeffected accidentally, and such re-exposure is prevented altogether ifthe cartridge 9 is removed from the needle assembly.

The particular form of the internal ribs 24 and on the sleeve 14requires use of a two-part moulding tool for moulding of the sleeve 14,and six equiangularly distributed windows 30 are provided in thevicinity of the apertured end 15 of the sleeve 14 in order to enablefingers provided on one part of the moulding tool to form the undercutsof the ribs 25 by way of the windows 30 at the same time as theremainder of the ribs 25 are being formed by the other part of themoulding tool by way of the opening 17 of the sleeve 14.

Such a syringe system utilizing pre-filled cartridges may be used in anyapplication in which disposable pre-filled cartridge systems arecurrently used. Furthermore it is envisaged that such a syringe systemwill replace existing reusable systems utilising pre-filled cartridgessuch as are used for administration of local anaesthetics in dentistry,for example.

Furthermore a broadly similar arrangement may be used in a syringesystem which is supplied pre-filled with injectate during manufactureand with a needle and plunger pre-fitted thereto. In this case thesyringe barrel will extend substantially the full length of theprotective sleeve, and the plunger will be integrally formed with apiston within the barrel.

Furthermore a similar syringe system may be used in applications inwhich injectate must be drawn up into the syringe barrel by insertingthe needle into an injectate bottle or vial before an injection isperformed. Such an operation requires exposure of the needle bytemporarily retaining the sleeve in its retracted position in order toenable the needle to be introduced into the bottle or vial. After a doseof injectate has been drawn into the syringe barrel by drawing back theplunger, the injection may be administered to the patient in a mannerbroadly similar to that described above with reference to FIGS. 8 to 12.A syringe system for use in such an application will now be describedwith reference to FIGS. 13 to 15.

Referring to FIGS. 13 to 15, the syringe system 51 comprises a barrel 52having at one end an outlet 53 and an integral needle connector 54 forattachment of the needle 55, and a plunger 56 displaceable within thebarrel 52. A sleeve 57 is mounted on the barrel 52 and is slidable alongthe barrel 2 between a contracted position (see FIG. 13) and an extendedposition (see FIG. 15). The sleeve 57 has an opening 58 through whichthe needle 55 projects when the sleeve is in the contracted position. Acompression spring 59 is located within the sleeve 57 between the needleconnector 54 and the end of the sleeve.

As may be seen more particularly in FIG. 15, the outer surface of thebarrel 52 is formed with a guide track 59A within which a projection 60(shown in broken lines) on the inside of the sleeve 57 engages. In orderto simplify assembly the sleeve 57 is formed in two parts, namely a mainbody part 61 of generally tubular form and an annular end part 62 havingthe projection 60 on its inside surface and having an outwardlyprojecting flange 63. During assembly, after fitting of the plunger 56within the barrel 52 and fitting of the spring 59 within the sleeve 57,the end part 62 is slid over the barrel 52 so as to introduce theprojection 60 into the track 59A from the plunger end of the barrel, andthe barrel 52 is then introduced into the body part 61 until a lockingarrow 64 on the end part 62 snaps into a complementary locking part 65of a slot 66 in the wall of the body part 61. In this manner the syringesystem is placed in its initial locked condition with the sleeve 57 inthe extended position shown in FIG. 3.

As may be appreciated more readily by referring to the explanatorydiagram of FIG. 14, the sleeve 57 is held in its initial extendedposition (FIG. 15) by engagement of the projection 60 within a recess69. The syringe is set to enable a dose to be taken up from an injectatebottle by applying a twisting motion to the sleeve 57 so as to bring theprojection 60 out of the recess 69 and so as to permit the sleeve 57 tobe manually drawn back to the contracted position with the projection 60moving along the track 59A. The sleeve 57 is temporarily locked in itscontracted position (FIG. 13) by applying a twisting motion to thesleeve 57 to cause the projection 60 to engage within the recess 67, asshown in FIG. 14. The needle 55 is then caused to pierce the cap of theinjectate bottle and the injectate drawn up by pulling back the plunger56. Subsequently the needle 55 is withdrawn from the bottle, this actionoptionally resulting in the projection 60 moving out of the recess 67 sothat the spring 59 moves the sleeve 57 into its extended position (FIG.15) shielding the point of the needle 55 in which it is locked by theprojection 60 engaging within the recess 69.

If required the needle used for filling the syringe may be re-sheathedand replaced by another needle for performing the actual injection.Subsequently, after removal of the protective sheath from the newneedle, air is expelled from the syringe in conventional manner, and, ifnecessary, the syringe is re-set by applying a twisting motion to thesleeve 57 and drawing the sleeve back to the contracted position (FIG.13). After location of the needle 55 at the intended site of injection,the dose may be administered by squeezing the syringe to depress theplunger 56. Initial depression of the plunger 56 causes the barrel 52 tobe forced inwardly against the action of the spring 59 and results inthe projection 60 engaging the ramp surface 68 so as to be forced out ofthe recess 67. Thus, on completion of the injection, as the needle 55 isremoved from the patient, the projection 60 moves along the track 59A asthe sleeve resumes its extended position shielding the needle in whichit is locked by engagement of the projection 60 within the recess 69.

Provided that the needle 55 is detachable from the needle connector 54,such a syringe system can be used with conventional needles. Furthermorea needle may be connected to or disconnected from the needle connector54 whilst the sleeve 57 is in its extended position shielding the pointof the needle, so as to avoid any danger of needle stick during such anoperation.

Re-sheathing of the needle 55 is performed by inserting a protectivesheath 70 into the sleeve 57 through the opening 58 at the end of thesleeve, as shown in FIG. 8. The sheath 70 is pushed over the needle hubso that internal ribs on the sheath 70 engage the outside of the needlehub. When a sheathed needle is to be connected to the needle connector54, the sheathed needle is inserted into the sleeve 57 through theopening 58 and the hub of the needle is screwed onto the needleconnector 54 by rotating the projecting end of the sheath 70, the sheath70 subsequently being withdrawn leaving the needle in position andshielded by the sleeve 57. Generally the needle connector 54 is a luerlock connector incorporating a tapered inner part over which the hub ofthe needle seats and an outer collar 71 having internal threads orprojections for engaging complementary formations on the outside of theneedle hub.

In order to remove the needle from the needle connector 54, an emptysheath is introduced into the sleeve 57 and engaged with the needle hubprior to unscrewing the needle from the needle connector 54 and drawingthe needle within the sheath 70 out of the sleeve.

I claim:
 1. A syringe system comprising an elongated hollow cylindricalbarrel (2) having an outlet (3) at one end of the barrel, a hollowpointed needle (5) connected to said one end of the barrel in fluidcommunication with the outlet, a plunger (12) within the barrel which isaxially movable by manual depression of the plunger from an outerextreme position outside the barrel to an inner extreme position withinthe barrel to expel liquid through the outlet (3) and along the needle(5), a protective sleeve (4) having an apertured end (15) and mounted onthe barrel (2) so as to be slidable along the barrel between acontracted position in which the needle (5) projects through theapertured end (15) of the sleeve (14) to enable skin puncturing to beeffected and an extended position in which the needle (5) is locatedwithin the sleeve (14) to shield the point of the needle, firstretaining means (22, 24, 26) on the barrel and the sleeve operable toretain the sleeve (14) in the extended position to shield the point ofthe needle (5), biasing means (19) mounted on the barrel and resilientlybiasing the sleeve (14) towards its extended position whereby the sleeve(14) automatically assumes its extended position, and is retainedtherein by the first retaining means (22, 24, 26), on release ofpressure applied in the direction of contracting movement, and secondretaining means (23, 24) on the barrel and the sleeve operable to retainthe sleeve (14) in the contracted position and to be automaticallyreleased by the beginning of depression of the plunger (12) out of saidouter extreme position to a position short of said inner extremeposition.
 2. A system according to claim 1, wherein the second retainingmeans comprises a latch formation (23) on the barrel (2) and aprojection (24) on the sleeve (14) which is engageable behind the latchformation (23) on the barrel (2) by relative twisting movement manuallyapplied between the sleeve (14) and the barrel (2) in order to retainthe sleeve (14) in the contracted position.
 3. A system according toclaim 2, wherein one of the latch formation (23) on the barrel (2) andthe projection (24) on the sleeve (14) has a ramp surface (29) which isengageable by the other of the latch formation on the barrel (23) andthe projection on the sleeve (24) upon depression of the plunger (12) toexpel liquid along the needle (5) in order to apply a relative twistingmovement between the sleeve (14) and the barrel (2) to thereby releasethe second retaining means.
 4. A system according to claim 1, whereinthe first retaining means comprises first and second formations (24, 26)on the sleeve (14) and a projection (22) on the barrel (2) which isengageable between the first and second formations (24, 26) on thesleeve (14) by means of a relative twisting movement between the sleeve(14) and the barrel (2) imparted by the biasing means (19) as the sleeve(14) moves towards its extended position.
 5. A system according to claim1, wherein the second retaining means comprises formations (23, 24)formed by external ribs (22) on the barrel (2) and internal ribs (24,25) on the sleeve (14) which cooperate to guide the sleeve (14) relativeto the barrel (2) during sliding of the sleeve along the barrel.
 6. Asystem according to claim 1, wherein the sleeve (14) comprises a tubularbody part within having an opening (17) in the end of the body partopposite to the apertured end (15), the barrel (2) being inserted insaid opening (17) during assembly, and an annular end part (18) which isformed separately from the body part and which is connected to saidopposite end of the body part on assembly in order to retain the barrel(2) within the sleeve (14).
 7. A system according to claim 6, whereinthe first retaining means (22, 24, 26) includes a recess (26) in theannular end part (18) which is located within the opening (17) in thebody part.
 8. A system according to claim 1, wherein the sleeve (14) isprovided with an outwardly projecting flange (16) at the opposite end ofthe sleeve to the apertured end (15) so that the plunger (12) is movableto expel liquid along the needle by depressing the plunger with thethumb of one hand whilst grasping the flange with the fingers of thesame hand.
 9. A system according to claim 1, which incorporates apre-filled cartridge (9), wherein the barrel (2) receives one end of thecartridge (9) therein in fluid communication with the outlet (3) wherebyliquid is supplied from the cartridge (9) to the needle (5) ondepression of the plunger (12), and wherein the other end of thecartridge (9) projects from the opposite end of the sleeve (14) to theapertured end (15) and is connected to the plunger (12).
 10. A systemaccording to claim 1, wherein said one end of the barrel (52)incorporates a needle connector (54) detachably connecting the needle(55) to said one end of the barrel, and the sleeve (57) has an opening(58) at its end through which the needle projects when the sleeve is inits contracted position, a needle sheath (70) for covering the needle,the opening (58) being of such a size as to enable said needle sheath(70) to be passed through the opening and over the needle when the pointof the needle is located within the sleeve in the extended position ofthe sleeve for the purpose of attaching the needle to or detaching theneedle from the needle connector (54).